Hot water dispenser faucet with thermal barrier

ABSTRACT

A faucet for a hot water dispenser has a valve metal body made of a metal having a thermal conductivity of 50 W/mK. A tube extends through a passage in the valve body and is coupled to a hot water line that extends into a hot water tank of the hot water dispenser and to a discharge outlet coupled to a discharge line that extends through a discharge spout. There is an air gap between a surface of the valve body surrounding the passage and the tube. The tube in conjunction with the air gap reduces heat transfer from the hot water flowing through the tube to the valve body. In an aspect, the tube is a plastic tube. In a variation, there is no air gap between the plastic tube and the valve body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/807011, filed on Apr. 1, 2013. The entire disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to instant hot water dispensers andfaucet therefor.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Instant hot water dispensers typically have a small electrically heatedtank for heating and holding hot water and a faucet coupled to the tankfor dispensing the hot water. The tank is typically disposed beneath asink, such as in a below-sink cabinet and the faucet extends up from atop of the sink.

In some hot water dispensers, both cold and hot water flow through thefaucet. The cold water flows through the faucet and the hot water flowsout of the tank through the faucet and out of a dispensing spout. Inthese types of hot water dispensers, the faucet often has a valve forthe cold water. Opening the faucet to dispense hot water opens the valveallowing cold water from a cold water source, such as a cold watersupply line in a house, to flow through the faucet into the tank. Thisforces hot water in the tank to flow through a hot water dispensing linein the faucet to the dispensing spout.

FIG. 1 shows a prior art faucet 100 of the above described typeavailable from the InSinkErator Division of Emerson Electric Co.designated the F3300 Faucet. FIG. 2 is a cross-section of a portion offaucet 100 showing in particular a cross-section of valve body 102 ofthe faucet of FIG. 1 and showing internal water flow through the valvebody 102. Faucet 100 includes valve body 102, dispensing spout 104extending upwardly from valve body 102 and handle lever 106 for openingand closing faucet 100, such as opening and closing a valve of a valvecartridge (not shown) disposed within valve body 102. A trim ring 108 issecured at a bottom 110 of valve body 102, such as with screws (notshown). Trim ring 108 may, for example, rest on a top surface, such as atop surface of a sink (not shown), when faucet 100 is installed. A hotwater line 112 extends downwardly from valve body 102 into a hot watertank (not shown) and has an inlet 116 typically disposed at a top of thehot water tank and an outlet 118 (FIG. 2) coupled to an inlet port 120(FIG. 2) of a hot water passage 122 (FIG. 2) extending through valvebody 102 to a hot water discharge port 124 (FIG. 2) that is coupled todispensing line 125 (FIG. 2) that runs through dispensing spout 104(FIG. 1). A check valve 126 (FIG. 1) is disposed in hot water line 112.A cold water supply line 136 has an outlet 130 (FIG. 2) coupled to acold water supply inlet port 132 (FIG. 2) of valve body 102 and an inlet144 (FIG. 1) coupled to a source of cold water (not shown). A cold watertank supply line 128 has an inlet 138 (FIG. 2) coupled to an outlet port140 (FIG. 2) of a cold water passage 142 (FIG. 2) in valve body 102 andan outlet 134 (FIG. 1) disposed in the hot water tank, typically at atop of the hot water tank.

As shown in FIG. 2, when faucet 100 is opened, cold water flows throughcold water passage 142 into cold water tank supply line 128 and throughcold water tank supply line 128 into the hot water tank. This forces hotwater to flow out of the hot water tank through hot water line 112 intohot water passage 122 in valve body 102 and through hot water passage122 to hot water discharge port 124.

Valve body 102 may be made of metal having a thermal conductivity of 50W/mK or more, such as brass that has a thermal conductivity of 109 W/mK.Since cold water passage 142 and hot water passage 122 are disposed invalve body 102 in close proximity to each other, there can be anappreciable heat transfer through the metal valve body 102 from the hotwater flowing through hot water passage 122 to the cold water flowingthrough cold water passage 142 causing a temperature drop in the hotwater flowing through hot water passage 122.

For hot water dispensers, it is important that the water temperature notdrop significantly as the hot water passes through the faucet from thetank. In faucets of the type described above, preventing a significanttemperature drop in the hot water as it flows through the metal valvebody can be a challenge as the hot and cold water pass in closeproximity through the faucet's metal valve body, which is may typicallybe a brass valve body.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In accordance with an aspect of the present disclosure, a faucet for ahot water dispenser has a valve body made of a metal having a thermalconductivity of 50 W/mK. A tube extends through a passage in the valvebody and is coupled to a hot water line that extends into a hot watertank of the hot water dispenser and to a discharge outlet coupled to adischarge line that extends through a discharge spout. An outsidediameter of the tube is less than a diameter of the passage so thatthere is an air gap between a surface of the valve body surrounding thepassage and the tube. The tube in conjunction with the air gap reducesheat transfer from the hot water flowing through the tube to the valvebody.

In an aspect, the tube is a plastic tube and the plastic tube acts as aprimary thermal barrier to reduce heat transfer from the hot waterflowing through the plastic tube into the valve body and minimize anytemperature drop in the hot water as it passes through the valve body.The air gap provides a secondary thermal barrier to further reduce heattransfer from the hot water flowing through the plastic tube into thevalve body.

In an aspect, the plastic tube is made from a plastic having a thermalconductivity of 0.26 W/mK or less.

In an aspect, the inside diameter of the passage is about 8 mm and thegap is illustratively about 2 mm.

In a variation, the tube is a brass tube.

In another variation, there is no air gap between the plastic tube andthe valve body.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a perspective view of a faucet for a prior art instant hotwater dispenser;

FIG. 2 is a cross section view of a portion of the faucet of FIG. 1;

and

FIG. 3 is a cross section view of a portion of a faucet for an instanthot water dispenser in accordance with the present disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

With reference to FIG. 3, a faucet 300 having a valve body 302 inaccordance with an aspect of the present disclosure is shown. It shouldbe understood that faucet 300 is the same as faucet 100 except for thedifferences discussed below. Valve body 302 includes a plastic tube 304extending through passage 305 with an inside 303 of plastic tube 304providing the hot water passage in valve body 302. Passage 305 mayillustratively be the same as hot water passage 122 of valve body 102with each having the same inside diameter. Plastic tube 304 may extendout through valve body 302 and couple to hot water line 112 outsidevalve body 302. An outer diameter of plastic tube 304 is less than aninside diameter of passage 305 so that there is an air gap 306 between asurface 308 of valve body 302 surrounding passage 305 and an outersurface 307 of plastic tube 304. Air gap 306 may illustratively be about2 mm when the inside diameter of passage 305 is about 8 mm. Plastic tubemay illustratively be made of a plastic having a low thermalconductivity of 0.26 W/mK or less, such as polysulfone. One or moreO-rings 310 may be disposed around a top end 312 of plastic tube 304.O-rings 310 hold plastic tube 304 in place within valve body 302 bycompression during assembly and also provide a water seal. Plastic tube304 is assembled with valve body 302 by a transition fit in closeproximity to trim ring 108. This positions plastic tube 304 relative tovalve body 302 to ensure proper compression of O-rings 310. The tightfit provided by the transition fit also minimizes the amount of waterleakage should the seal provided by O-rings 310 fail.

Plastic tube 304 in conjunction with air gap 306 reduces heat transferfrom the hot water flowing through plastic tube 304 to valve body 302.Since the thermal conductivity of plastic tube 304 is substantially lessthan that of metal, particularly brass and copper, plastic tube 304 actsas a primary thermal barrier to reduce heat transfer from the hot waterflowing through plastic tube 304 into valve body 302 and minimize anytemperature drop in the hot water as it passes through valve body 302.Air gap 306 provides a secondary thermal barrier to further reduce heattransfer from the hot water flowing through plastic tube 304 into valvebody 302. Coupling hot water line 112 to plastic tube 304 furtherreduces heat transfer since hot water line 112 is no longer in contactwith a metal valve body.

In a variation, a brass tube is used instead of plastic tube 304.

In another variation, valve body 302 includes plastic tube 304 in hotwater passage 122 without air gap 306. That is, the outside diameter ofplastic tube 304 and the inside diameter of passage 305 are the same sothat an outer surface of plastic tube 304 abuts the surface 308 of valvebody 302 surrounding passage 305.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

What is claimed is:
 1. A faucet for a hot water dispenser, comprising: ametal valve body having a passage therein, the metal of the metal valvebody having a thermal conductivity of 50 W/mK or more; a tube thatextends through the passage in the valve body, the tube coupled to a hotwater line that extends into a hot water tank of the hot water dispenserand to a discharge outlet that is coupled to a discharge line thatextends through a discharge spout of the faucet; and an air gap betweenan outer surface of the tube and a surface of the valve body surroundingthe passage and the tube.
 2. The faucet of claim 1 wherein the tube is aplastic tube, the plastic tube in conjunction with the air gap reducingheat transfer from the hot water flowing through plastic tube to thevalve body wherein the plastic tube acts as a primary thermal barrier toreduce heat transfer from the hot water flowing through the plastic tubeinto the valve body and minimize any temperature drop in the hot wateras it passes through the valve body and the air gap provides a secondarythermal barrier to further reduce heat transfer from the hot waterflowing through the plastic tube into the valve body.
 3. The faucet ofclaim 2 wherein the metal valve body is a brass valve body.
 4. Thefaucet of claim 2 wherein the plastic tube is made from a plastic havinga thermal conductivity of 0.26 W/mK or less.
 5. The faucet of claim 2wherein the inside diameter of the passage is about 8 mm and the gap isillustratively about 2 mm.
 6. The faucet of claim 2 including at leastone O-ring disposed around a top end of the plastic tube between theplastic tube and the valve body.
 7. The faucet of claim 1 wherein theinside diameter of the passage is about 8 mm and the gap isillustratively about 2 mm.
 8. The faucet of claim 1 wherein the tube isa brass tube.
 9. The faucet of claim 1 wherein the valve body is a brassvalve body.
 10. A faucet for a hot water dispenser, comprising: a metalvalve body having a passage therein, the metal of the metal valve bodyhaving a thermal conductivity of 50 W/mK or more; and a plastic tubethat extends through the passage in the valve body, the tube coupled toa hot water line that extends into a hot water tank of the hot waterdispenser and to a discharge outlet that is coupled to a discharge linethat extends through a discharge spout of the faucet.
 11. The faucet ofclaim 10 wherein the plastic tube is made from a plastic having athermal conductivity of 0.26 W/mK or less.
 12. The faucet of claim 11wherein the metal valve body is a brass valve body.
 13. The faucet ofclaim 10 wherein the metal valve body is a brass valve body.